Aluminium in alkali. Chemistry help please.

[anachronism]

I think what Lou meant by "making the pieces to be stripped anodic" is merely to have them connected to the positive terminal.

Yep I'm good with that Ralph. I was meaning that I've got a simple way to make a large quantity anodic.

 

[Platdigger]

I must have read your post wrong. For some reason I thought you said "base metal" not "base material".
My bad.
Oh, by the way Anachronism, it's not Ralph, but that's ok.

 

[anachronism]

I must have read your post wrong. For some reason I thought you said "base metal" not "base material".
My bad.
Oh, by the way Anachronism, it's not Ralph, but that's ok.

Yeah my apologies I read your post "on the fly" as I was leaving this morning!

 

[goldsilverpro]

For gold on an aluminum base, nickel or no nickel, I have always used the electrolytic concentrated sulfuric stripper (so-called reverse plating). Works great but, as always, you should keep the current low enough to not exceed a solution temp of about 100F-105F. I have mentioned this several other times on the forum. I have even stripped fairly thick gold coatings (say, 3-5 microns) without affecting the Al. However, there are lots of different Al alloys out there and I haven't tried them all. From my experience, though, I would expect them all to work.

 

[anachronism]

Thanks Chris.

 

[Geo]

That's a head scratcher. Are you sure there's not a copper or nickle strike beneath the gold layer? I only ask because I have never seen gold directly on aluminium before. I normally don't recommend it but a prolong leech in dilute HCl may bring the gold off in large sheets without dissolving the whole piece.

 

[anachronism]

That's a head scratcher. Are you sure there's not a copper or nickle strike beneath the gold layer? I only ask because I have never seen gold directly on aluminium before. I normally don't recommend it but a prolong leech in dilute HCl may bring the gold off in large sheets without dissolving the whole piece.

Thanks for the valued input Geo I appreciate it. The thing is, I'm looking at tonnes of product per month and prolonged soaks don't cut the mustard when it's got to be processed and out the door.

Jon

 

[g_axelsson]

That's a head scratcher. Are you sure there's not a copper or nickle strike beneath the gold layer? I only ask because I have never seen gold directly on aluminium before. I normally don't recommend it but a prolong leech in dilute HCl may bring the gold off in large sheets without dissolving the whole piece.

Here is one example of gold directly on aluminium.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=19177&start=20#p194541

Göran

 

[Geo]

That's a head scratcher. Are you sure there's not a copper or nickle strike beneath the gold layer? I only ask because I have never seen gold directly on aluminium before. I normally don't recommend it but a prolong leech in dilute HCl may bring the gold off in large sheets without dissolving the whole piece.

Here is one example of gold directly on aluminium.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=19177&start=20#p194541

Göran

Very nice. I suppose there will be examples of just about any combination and configurations of stuff like this.